Hydraulic remote control system



June 10, 1947. w, SHERIDAN HYDRAULIC REMOTE CONTROL SYSTEM Filed July 1, 1943 2 Sheets-Sheet 1 ATTYS June 10, 1947. H. w.- SHERIDAN HYDRAULIC REMOTE CONTROL SYSTEM Filed July 1, 1943 2 shets-sheet 2 W IIITVENT OR. l'ldazz,

1 AIT'YS BY [1mm Patented June 10, 1947 HX EAULIC REMO QN' TE LS TE Hiram Sheridan, Oak Bark, 111.

Application; J il 1., 1943, Serial LNc-l 93,039

7 4 Claims. (01. 60-545) This-invention relates, to hydraulically operated devicesior the remote controloij mechanism of various types. 7

p c p o i t fithe inventi n is, he Pro s n e and mproved" hyd aulic c t l de e f r cnera inevarious;typeset me n s by, mc e ontr An th r ob e t oi h inveniionis the provision ew a d improved ydrau ic controlvv mechnism that hasno el means or compensating for expansion and contlZactiQno f. thehydraulic fluid ithout affecti g the. operat on of.- he c nt me hanism.

A inrther. object o the invention. is e pro= vision of new and mp oved,- hydraul c ma h:-

anismcforon ratine mote con ols eiieotin the ir c iv movemen s. f airpla e d r e bhaand l v s. and that is substantially n n-com pressib e a dnonx ensible.

A. iurther object. E th -d ce s e envision of a. remote control. unitof th h draulic type that ii n mn essitle an nQ Xtensible a er all temperature conditionsi h rehy he di ancebetwee he operating elemectand the erated or contro led memb r" emains c ema ingthe-invention therein more on less diagram-r matically;

Fig.f2'- is-a: diagrammatic view ofthe remotecontrol'mechanism, showing the same in neutral position;

Fig; 3'is'asimi1arviewofthe mechanism, showing the sameafter it'hasbeen operated;

Fig. 4 lsa plan-viewof a portion of the device, shown more or less; diagrammatically;

Fig, 5 is a horizontal section of 'a portion, of the device, showing amodified construction;

Fig-:6 is a section on the line,6-6=of Fig, 7'; and

Fig; 7" is a horizontal section of'another Fo ,2 tion of the device, showing aflirthermodified construction.

In aerial transportion th vehicle is directed;

by means of elevators, ailerons, and a rudder,

The control connections for these elements are of considerable length and usually have more or less give, elasticity or rubber efiect while use. Furthermorathe effect ofheat; andcold on these connections expands and contracts them-anomaterially complicates this give and takeo yielding movement. The present invention seeks to remedy these difliculties by the provisionof'liquid' columns for transferring steering 'energ-y from the control levers to"the control'mechanism thatis so, constructed and. arranged that these 001'- umnsorconnections are not; affected by; variations in temperatures to whichthey are'contim allysu jecte 7 It is contemplated that the invention may be adaptedito various remote control; purpose 'in-.

cluding remote control for radios, cameras and other devices.

The invention is based; on the concept of-employing two separate hydraulic columns so related that while the; two columns will cooperate for remote actuation, expansion andcontraction of the fluid in thescolumns with changes in temperature will in efiect cancel out without causingfl actuation Such cancellation avoids inaccuracy or mal functioning attributable, to either ng s temperatur or chang s n en r mental pressure,

heme hydraulic columns ne d e each is made to have the same volume asthe,

other one which is usually done by having; all

parts eq al' n mensions and by v n hefiu d' lines the same length, but theflexibilityof the device is. such that-one, pipe line can be made much shorter than the other ii installation problemsma'ke, it desirable The difference in volume of one line with respect to the other line is adjusted by means of a small reservoir of controllabl capacity, as with a metal-plug, so that;

the volume of fluid one line system ca be made exactlyequal to that in the other; line system: If' desirable, two-reservoirs are used. one to each line,

To make the compensator work with precision two things are necessary. The volume of fluid" in the syst m of the two lines should be equal, one

to the other. Second, the two columns of fluid must be affected by the same changes of temperature. Ordinarily the two columns will naturally have the same temperature, and this is no problem, but it is well to bear in mind that, in a steel mill, for instance, one line should not be run in the red glare of a furnace, while the other is behind some thermal insulation.

Referring now to the drawing, the reference character Ill designates an aircraft having the fuselage II, the cockpit l2, the wings l3, I4, the rudder l5, propeller l6, and the landing gear IT. The rudder is pivoted to swing about a vertical axis l8, as shown in Fig. 1 of the drawing. The control stick is shown at l9, therudder bar at 2|, and the seat at 22. The invention is disclosed in connection with the control of the rudder, and V Y j o'fthe piston 35 will force it and the rack 36 upwill now be described.

As shown more particularly in Figs. 1' to 4 in- 1 r elusive, the rudder staff 23, on which th'e'ru'dder bar 21 is fixed, is provided at its lowerend with a gear 24, which meshes with racks-25, 26, ex-

tending in the same directionand arranged at opposite sides of the gear 24. The rudder'istaff i" 23 is rotatably mounted'in fixed pivots, and the racks 25, 23,;areconnected to pistons 21, 28, whichreciprocate in cylinders 29, 3|. The cylinder 29 is in communication at, what for convenience of description will be termed, its rear end, with a pipe or conduit 32, which extends at a distance to the compensating device or operating mech anism, shown generally by the reference character 33. The rear end of the conduit 32 is in communication with a cylinder 34, having apiston 35 therein, which is rigidly connected we rack bar 36. .The rack bar 36 meshes with a 3 The gear 31 is a floating gear, andis adapted. to have not only a rotary motion but a motion of pure translation. Pivotally connected to the gear 31 is an actuating rod 45, Fig. 4, which'has a rack 41 on its outer end. The'rack 41 is in engagement with agear 48, and this gear is mounted on the pivoted shaftlB of the rudder |5..

The rack 41is provided with a suitable guide, as 49, and the racks 43 and 33 are provided with suitable guides 5|, 52. Likewise the racks 25, 26, are provided with guides 250, 260. The conduits 32 and 38 may be of any suitable length, and are adapted to be filled with a liquid, preferably one that will not be affected by freezing weather.

Assuming now that the control apparatus is in theposition shown in Figs. 1 and. 2,.andassuming that the temperature has increased materially,-the liquid in the conduits32 and 38 will expand, and since the racks 25, 26 ,are on the opposite side of the gear 24 and extend in the same direction, and since the gear is mounted' on a shaft having fixed pivots, there will be no movement of the racks 25, 25, because they .tend to rotate the gear 24 in opposite directions about a fixed pivot, and consequently the liquid cannot expand in that direction. Expansion of the liq-, uid, however, will causethe -pistqll fi 81 .1 1

3| is likewise in connection with:

to move outwardly in the cylinders, and since these pistons are arranged at opposite sides of the gear 31 and move in opposite directions they will merely rotate the gear 31 without in any way affecting a translating movement of the gear 43.

Assume, now, that the rudder bar 2! is rotated left-handed, this will cause the rack bar 26' (see Fig. 1) to move rearwardly, and this in turn will cause the liquid column 53 in the conduit 38-to move rearwardly, and this in turn will cause the piston M to move upwardly, as shown in Fig. 3;

' pistonZTmoves to the left it'will create-a partial vacuum, and the air pressure on the outer end Wardly in said figure, in the direction of the arrow 55. Since both the rack bars 43 and 36 are moved upwardly, they will carry the floating gear 31. upwardly without rotatin it, from the.

dotted lineposition' shown in Fig. 3 to the full line position shown therein in the direction indicated by the arrow 51 in this figure.

The movement of the gear 3! from the dotted line to the full line position will move'the rack- 1 bar 46 upwardly in Fig. 4, and this. in turn will; rotate the gear 48 on the rudder bar 18, thereby moving the rudder I5 to the left asviewed from the rear of the aircraft. By rotating the shaft 23 in the opposite direction, the rudder maybe moved to the right. It will thus be seen that the expansion or contraction of the. liquid in the conduits will compensate or equalize each other,

the particular elevation at the time the mecha- V nism is operated. In order to render the device independent of air pressure in its operation, the

following mechanism maybe employed.

The outer or adjacent ends of the cylinders 34 and 39 are connected' by a conduit or passage 58, having a compensating device 59 inserted therein, Fig, '7. The compensating device is in-' V serted at'any suitable point in the conduit 58" and is intended for compensating for the in-: crease in volume of the liquidin' the conduit 58, due to increase in temperature. As shown,

an annular box member or compensating casing- BI is provided, to the walls of 'whichthe adas shown in Fig. 6. vided with a bottom section 62, and a top secv tion 63, which are connected together in any suitable manner, as by means of bolts 64 engaging flanges 65, '33, on the upper and lower sections of the box. Clamped between the flanges 65, B6, is a yieldable diaphragm, such as a corrugated steel plate 61: The. diaphragm has a rigid plate 68 adjacent its central portion, and the plate has an upwardly extending-stud, 69 which constitutes a guide for a. spring H the lower end of which surrounds the stud GQ'fllld" the upper end of which engages about-areduced portion 12 or an adjusting screw 13 threaded thru the upper wall of the box memand spring to yield for increasing the volume of; the; compensating casing. The expansive force of the fluid being tremendous, the parts will yield toeompensate for; this expansion but will function-more or less like. ari-gid member for transmitting force from one. piston to the other. It Wi l thus'be seen that when the bar 231 is rotated counterclockwise, and the piston 4| is forced upwardly, itwill force the liquid in the passagei58 upwardly in.F ig.. '7 and this in. turn will forcethe piston 35. upwardly the: same amount; By increasing the pressure on: the diaphragm H with the inner end of'the screw 13, almost-any pressure desiredmay be applied.- to the outer end of the piston 35 for moving the same.

In Fig. 5 is shown a modified form of construction in which the leakage past the pistons 27a and 28a may be prevented, or at least compensated for, and this is accomplished by the provision of a casing member 59a which is similar to the casing member 59 shown in Fig. 6. Thi casing member 59a may be termed a reservoir, and is filled with a liquid which may be maintained under pressure at all times by any suitable means known to the art (not shown). Should any of the liquid leak past the piston rods or rack bars that form piston rods 25a, 26a, the liquid under pressure in the reservoir 59a will compensate for this leakage.

It is desirable that the conduit 32a and 53a maintain a constant relative amount of the liquid, and in order to insure this equilibrium a cross-over conduit 14, having a valve therein, may be provided. When the device is in neutral position, as shown in Fig. 7, the valve 15 is in closed position. Should some of the liquid leak out from either the conduit 32a or 53a, the valve may be opened and the device reset to neutral position, that is, the pistons 35 and 4| are moved to the proper position, after which the valve 15 is again closed.

While in the constructions disclosed a rack and pinion is shown for convertin reciprocating into rotary motion, it is understood that any of the mechanical devices conventionally employed for this purpose may be used.

The type of fluid employed will be selected for desired results. Low friction fluid, such as alcohol, may be used when viscosity of the fluid is the major consideration. In applications such as the control of airplanes, where very low temperatures are encountered, the oil now in current use, and known to the trade as Sperry fluid or similar composition, could be used. Where damping against oscillations is most desired, a fluid of heavier viscosity would be employed. Where seepage is the major consideration, a fluid that does not leak through small openings would be utilized.

Expansion of a fluid column can be compensated for by the use of a reservoir or fluid container attached thereto. The volumetric content of the reservoir may be controlled by the action of a thermostat, so adjusted that the expansion of the hydraulic column through a rise of temperature would be compensated for by a corresponding increase in the volumertic content of the reservoir, thus taking sufficient fluid out of the column to maintain the column always at even length.

It is thought from the foregoing, taken in connection with the accompanying drawings, that the operation and construction of my device will be apparent to those skilled in the art,

. 6' and thatchanges in size, shape, proportionl and details may 'be madefiwith'out departing from the spirit and scope. of. the appended claims.

I claim as my invention:

1. In a control device, an-operating member comprising agear rotatable about a fixed axis, an operated member comprising. a. gear. adapted to rotate and having a motion of pure translation, a pair of hydraulic columns'betw-een-said members, acylinder at each end of said co1u mns,..a piston in each cylinder, a rack connectedrto: each piston; the racks at the, inner ends of said. colurnns being-parallel and extending in the same .il-efiti'flil the rack at the outer ends of said columns being parallel and extending in QDpQsite directions, whereby when said hydraulic columns expand they will cause the rotation of the outer gear only and when said inner gear is rotated in either direction it will cause the outer gear to mov in a plane parallel to said outer racks, and a passage between the outer ends of each pair of cylinders for assisting in preventing leakage past the pistons in said cylinders.

2. In a control device, an operating member comprising a gear rotatable about a fixed axis, an operated member comprising a gear adapted to rotate and having a motion of pure translation, a, pair of hydraulic columns between said members, a cylinder at each end of said columns, a piston in each cylinder, a, rack connected to each piston, the racks at the inner ends of said columns being parallel and extending in the same direction and the racks at the outer ends of said columns being parallel and extending in opposite directions, whereby when said hydraulic columns expand they will cause the rotation of the outer gear only and when said inner gear is rotated in either direction it will cause the outer gear to mov in a plane parallel to said outer racks, a passage connecting the outer ends of the outer cylinders, a resilient diaphragm for yieldingly increasing the capacity of said passage, and means for varying th stiffness of said diaphragm.

3. In a control system, an operating member movable in opposite directions for opposite control effects, a, first pair of cylinders enclosing a first pair of pistons connected to said operating member to move in opposite directions in response to movement of said operating member in one of its directions, a floating rotary operated member, a second pair of cylinders enclosing a second pair of pistons operatively connected with said operated member to cause translation of the operated member in response to simultaneous movement of said second pair of pistons in one direction and to cause rotation of the operative member in response to simultaneous movement of said second pistons in opposite directions, two hydraulic columns operatively interconnecting said two pairs of cylinders to cause said second pair of pistons to move in the same direction in response to movement of the first pair of pistons in opposite directions and cause the second pair of pistons to move oppositely in response to fluid expansion by temperature changes in the two hydraulic columns, and means providing hydraulic communication between outer faces of at least some of said pistons to minimize fluid leakage from said two hydraulic columns.

4. A control system as set forth in claim 3 in which said means providing hydraulic com munication includes means providing hydraulic communication between the two outer faces of said first pair of pistons, and separate means pro- 7 iding hydraulic communication between .the out-x enfaceso'f said'se'cond pairof pistons.

HIRAMW. SHERIDAN.

,1 7 REFERENCES CITED "'Theff ollowing"referencs are of record in the file 9f c s WWW T STATESVPATENTS Numbr Name Date 375;674 Greene Dec. 2'7, 1887 1,716,121 'Giffen June 4, 1929 2,205,046 Nardone June 14, 1940 2,297,610 Giers Sept. 29, 1942 2,308,048 Brown Jan. 12, 1943 France Jul 's, 1936 

